Global warming trumps climate change?

So much of the online climate "debate" is about effective communication, not science. Earlier this week, I met with a public opinion expert who critiqued the way many scientists and environmental groups speak about, er, climate change, no global warming, maybe the climate crisis, global heating, countdown to a meltdown, springtime for CO2, waterworld, the greatest threat facing humanity, well, you know what I mean.

The expert raised example after example of scientists, NGOs, government, etc. shooting themselves in the foot while talking about, um, the impact of human activity on the climate system. Take the oldest argument of them all: global warming or climate change?

At right is the Google trends graph of average worldwide searches for global warming (in blue) and climate change (in red). The top graph is standard Google searches, the bottom graph is news references.

The graph shows that "global warming" is far more common a search term. The average person is more likely to use and recognize the label "global warming", as evidenced by the search volume. But "climate change" appears more often in the news. Why? In no small part because all the writers, and especially all the people quoted in the articles, say "climate change".

Now, we can argue the semantics of the different terms. Generally, scientists reject the term "global warming", because it is not used in the literature and supposedly "less accurate" because the entire planet is not warming at the same rate. I've used that argument many times, and now wonder if it may be a mistake to do so (as has been pointed out to me, "global" simply implies the whole planet is warming, which is true!).

Rights and wrongs of the different labels aside, the fact is that there is a disconnect here. We use a term that means less to people. And it puts scientists and others communicating the real scientific consensus at a disadvantage. Do a Google search for "global warming" and "climate change". With "global warming", the term the public is more likely to use, a "skeptical" site comes up second [note: search is done from Canada, others may find different results].

Global warming is the science of how human released optically active gases like CO2 and CH4 and others affect the radiative balance of the atmostphere. Along with land use changes that affect albedo and mousture. Right at the moment the best science tells us quite accurately that the forcing is positive and will cause warming of the atmosphere quite above natural forces at this point in the interglacial cycle.

Climate change is the result of this warming. As the earths atmosphere is so complex and its relationship with the Earths surface it not really fully understood it is not possible to accurately predict the magnitude and ramifications of this. However we know enough from computer models and historical climate change that there could be profound changes from small amounts of warming affecting billions of people.